#include <stdio.h>

int main(void){
  int count=0,sum,score;
  do{
    count++;
    printf("请输入第%d个学生成绩：",count);
    scanf("%d",&score);
    if(score==-1) break;
    sum+=score;
  }while(score!=-1);
  if(count==0){
     printf("你没有录入任何成绩!\n");
  }else{
    printf("平均分:%d\n",sum/count);
  }
}
